Trailer Plug Problem

[Ian H]

A 3 way fridge will run off 240v, gas or 12v and should be capable of running off the van internal battery. Most (not all) customers i have dealt with want the anderson plug wiring to the van battery to keep it charged.

I've never come across a caravan fridge running off the caravan battery simply because it doesn't need to being able to run on gas. On the road, it probably doesn't matter if it ran off the van battery since that's also under charge from the car but I've never seen one wired like that and I assume it's so the fridge doesn't remain on 12v charge after the car is unhooked. It would flatten the battery if you forgot to change it over to gas whereas if it runs off the car and the car is diconnected, there's no chance of a flat battery.

[PaulMcG]

My van (new, 2019,) purchased off the floor, so no chance to have any custom modifications on the build, came supplied with a 12 pin flat, with two of the pins supplying directly to the 3 way fridge. There is no capability for the fridge to run off the 12 volt caravan house battery.

The two options I was presented with was either have the Pajero changed to a 12 pin flat, and run power back from the start battery and wired into this plug, (quoted $500+ for this), or have the van changed to a 7 pin flat, with a separate Anderson plug split out of the loom for the fridge wiring power supply. ($70).

I chose the second option, then run twin core 6 B&S (13.5 mm2) cable myself from the Pajero start battery back to an Anderson plug, via an ignition triggered relay, and a voltage sensitive relay for a second layer of assurance to prevent draining the start battery.

I didn't measure the size of the terminals for the power supply pins on the 12 pin plug, but they didn't look like they would have accepted 6 B&S, which I specifically wanted to run to eliminate voltage drop. (End result was < 0.2 volts drop from battery to plug).

[Jasonmc73]

As for current rating, I wouldn't want to charge a van battery or run a 3 way fridge via the 7 pin plug. While the pins themselves are probably capable of handling the current I doubt that a suitable size wire (I'm thinking in the order of 20A, oversized for voltage drop) would fit. This doesn't mean others haven't done it, it's simply not something I would waste time with - a separate 50A Anderson with chunky cables would be a better solution.

Agree,

I spent time today running 4B&S cable amongst other wires in a NX. Distance = size

The wire will run Redarc BCDC 40amp charger in my camper. Fair enough this wire probably run 4 or 5 fridges though

Also picked up on here easy spot for ignition source wire due to smart alternator, via A air con relay, perfect location easy to get at.

The wires continue when Jaycar opens tomorrow , public holiday here today.

[Dicko1]

I've never come across a caravan fridge running off the caravan battery simply because it doesn't need to being able to run on gas. On the road, it probably doesn't matter if it ran off the van battery since that's also under charge from the car but I've never seen one wired like that and I assume it's so the fridge doesn't remain on 12v charge after the car is unhooked. It would flatten the battery if you forgot to change it over to gas whereas if it runs off the car and the car is diconnected, there's no chance of a flat battery.

I think you will find that many vans are capable of running off a 12 volt house battery. Once your car stops...your fridge stops if not connected to a house battery. . Most vans also have solar feeding the house battery. The people I know with vans all have them connected to the house battery for the many times they may stop for a few hours on the side of the road, sightseeing or even just travelling with their car charging the house battery. Gas gets flicked on only for overnight stays or longer.. With the advent of powerful, lightweight lithium batteries leaving even a power hungry 3 way fridge on for 12 hours wont hurt anything.

[Jasonmc73]

I think you will find that many vans are capable of running off a 12 volt house battery. Once your car stops...your fridge stops if not connected to a house battery. . Most vans also have solar feeding the house battery. The people I know with vans all have them connected to the house battery for the many times they may stop for a few hours on the side of the road, sightseeing or even just travelling with their car charging the house battery. Gas gets flicked on only for overnight stays or longer.. With the advent of powerful, lightweight lithium batteries leaving even a power hungry 3 way fridge on for 12 hours wont hurt anything.

Hence i'm running 4 B&S cable in my car to power BCDC 40amp charger to charge house batteries in camper.

The 120amp Anderson plug at the back of car is my power plant basically + solar

As you can tell i'm not really into voltage drop/ small wires & plugs

I hired a camper van in NZ, made by Bursner, a german built machine.
Now that was a nice fridge, which i guess is what your talking about?
Fully automatic, switched between car, house battery & gas all by itself, most times.
Only thing one had to do was turn gas on/off, it wasn't smart enough to do that function.

[2bad4u]

My car doesn't charge the caravan at all, everything is done by solar. Anderson plug is to run the fridge via my dual battery system and pin 2 is 12v+ for the ESC.